Periodic Reporting for period 2 - SLOWD (Sloshing Wing Dynamics)
Periodo di rendicontazione: 2021-03-01 al 2023-08-31
SLOshing Wing Dynamics (SLOWD) aims to investigate the effect of sloshing on the dynamics of flexible, wing-like structures carrying a liquid (fuel), through the development of experimental, numerical and analytical methods. Primarily it looks to positively use the effect of sloshing to reduce the undesirable loads occurring from gusts and turbulence. Its main goal is to provide a holistic approach (both experimental and numerical) in order to quantify the energy dissipation effects associated with the liquid movement inside the fuel tanks, as the wing undergoes dynamic excitations. An increase of the order of 50% in the damping characteristics of the structure is expected.
The primary focus of the project is the application of modelling capabilities to the wing design of large civil passenger aircraft (subject to EASA CS-25 type certification), which are designed to withstand the loads occurring from atmospheric gusts and turbulence and landing impacts. SLOWD is the first project to propose full scale wing tests which include slosh dynamics. The proposed work is therefore aiming to advance the state-of-the-art capabilities in the field of sloshing/structure/control interaction to increase significantly the international competitiveness of the European aerospace industry. Also, it aims at making recommendations to EASA so as to make aerospace design practices safer and more competitive.
Main Objectives:
1) Setup of an Experimental Campaign to investigate the response to dynamic loading of the wings of a modern passenger airliner (200 passengers or more) carrying fuel.
2) Further Develop Numerical Methods for the concurrent modelling of the experimental setup and generation of a high-fidelity in-silico representation.
3) Evaluate Reduced-Order and Analytical Models, as surrogates of the numerical models for subsequent inclusion into an industrial design framework.
4) Integration of the Models into a Multidisciplinary Design Framework using an industrialized version of the developed software to understand the influence of design parameters and define an optimal architecture of the wing fuel tanks, which maximizes the dissipation effects due to fuel sloshing.
WP1 was led by the coordinating entity Airbus Operations, with support of EASN-TIS, and dealt with the scientific coordination and financial/administrative management of the project.
WP2 Main Findings:
- One DOF transient response rigs: Identified turbulent, lateral sloshing, and low-motion phases.
- One DOF harmonic rigs: Frequency and amplitude affect damping levels.
- Scaled (3m long) wing model: Realistic 3D multi-DOF test case for scaling.
WP3 Main Achievements:
- Use SPH models and VOF code for slosh-induced load simulation.
- Accurate modeling of 2D and 3D slosh cases.
- Develop scaling laws for aircraft design.
WP2 Main Findings:
- One DOF transient response rigs: Identified turbulent, lateral sloshing, and low-motion phases.
- One DOF harmonic rigs: Frequency and amplitude affect damping levels.
- Scaled (3m long) wing model: Realistic 3D multi-DOF test case for scaling.
WP3 Main Achievements:
- Use SPH models and VOF code for slosh-induced load simulation.
- Accurate modeling of 2D and 3D slosh cases.
- Develop scaling laws for aircraft design.
WP4 Main Achievements:
- Enabled support for high and low fidelity FSI analyses.
- Shared small-scale wing structural model and experimental data with SLOWD partners.
- Gained insights and calibrated models for nonlinear damping in dry structures.
- Proposed ad hoc models to capture nonlinear effects in aerodynamics and dry damping.
- Described amplitude and frequency characteristics arising from geometric nonlinearity.
- Contributed to FSI coupling understanding and SPH/ROM model development.
WP5 Main Achievements:
- Created new software capability for high-performance sloshing simulation.
- Studied fluid slosh effects at varying Froude numbers and baffle setups.
Key Findings:
- Achieved coupled FSI simulation with commercial closed-source solutions.
- Importance of high-fidelity CFD for sloshing dynamics.
- Baffled regions' impact on damping behavior.
- SPH and VoF both suitable for different sloshing scenarios.
WP6 Main Achievements:
- Accurate sloshing behavior reproduction in diverse applications.
- Pressure ROM computes tank wall pressures precisely & faster than detailed CFD.
- Linearized Frequency Domain technique applied successfully to different tank shapes for small perturbations.
- Bouncing ball models, Neural-Network-based ROMs, and surrogate models predict sloshing-induced responses.
- Integrated ROMs demonstrate load alleviation in gust response analyses.
WP7 was coordinated by Ariane Group, and provided all partners with the software for the industrial use of the methods and tools of WP5 and 6.
Main Achievements:
- Comprehensive software managing project structure and configuration data.
- Key Functionalities: system coordination made easy, flexible configuration options, seamless communication with other work packages, efficient simulation restart, impressive results plotting.
WP8 managed the exploitation and dissemination of the SLOWD results. Led by EASN-TIS with support of Airbus and Airbus Defence & Space, the activities in this work-package have resulted in a strong social media and web presence for the project.
Advancement in multidisciplinary capabilities for whole Aircraft:
- Integration of methods into the industrial design with potential applications to already certified aircraft.
- Avoidance of expensive and unnecessary structural reinforcements / weight increases.
- Savings on total wing weight with direct impact on fuel consumption.
- Exploiting conservatism in existing designs to increase the variety of active and passive load control strategies for optimal aircraft design.
This was achieved thanks to the deliverables of WP2, 3 and 4, which allow to characterize the fundamental physical phenomena and their main driving parameters.
Reduction in the aircraft design cycle and higher complexity decision trade-offs:
- Optimal design in a shorter time frame.
- Innovative design solutions, novel wing tank layouts.
- Target weight savings of 6% (twice that achievable for an existing design).
This was achieved thanks to the deliverables of WP5 and 6, which allow to model the sloshing phenomena as part of a larger, more complex, system
Development of synergies on visualization methods & big-data analytics:
- Integration of full order and reduced order / analytical models.
- Interpretability of simulation results and comparison of the accuracies of the different types of models.
- Identification of the key simulation parameters and development of visualization/analysis techniques.
This was achieved thanks to output of WP7, which eases the use of the methods and tools developed in the other work-packages
Increase the European innovation potential in Aeronautics and Air Transport:
- Exchange of personnel between large aerospace groups SMEs and Academia.
- Involvement of partners active in space-industry and other transport sectors, for cross fertilization of ideas.
This was achieved thanks to several personnel exchanges between academic partners and industrial placements of researchers.